By default when you use the Silverlight.js library to load a
Silverlight control in a page, it will automatically detect whether Silverlight
is installed on the visiting client machine, and if not prompt the user to
install it via an install image the Silverlight.js library automatically
injects into your page.
This default installation option is a model we call the
"indirect install" option - because when the user clicks the install
link it automatically opens up a new window with the Silverlight EULA and
download page on Microsoft.com displayed.
The benefit with the indirect install option is that it
though, is that your visitors will end up navigating to a separate page to
install Silverlight, and the overall end user experience won't feel super
integrated within the rest of your site.